Smithsonian Miscellaneous Collections Volume 139, Number 2
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SMITHSONIAN MISCELLANEOUS COLLECTIONS VOLUME 139, NUMBER 2 THE BIRDS OF ISLA ESCUDO DE VERAGUAS, PANAMA (With One Plate) By ALEXANDER WETMORE Research Associate Smithsonian Institution (Publication 4378) a CITY OF WASHINGTON PUBLISHED BY THE SMITHSONIAN INSTITUTION JULY 8, 1959 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOLUME 139, NUMBER 2 THE BIRDS OF ISLA ESCUDO DE VERAGUAS, PANAMA (With One Plate) By ALEXANDER WETMORE Research Associate Smithsonian Institution (Publication 4378) CITY OF WASHINGTON PUBLISHED BY THE SMITHSONIAN INSTITUTION JULY 8, 1959 JUL o6 1953w THE LORD BALTIMORE PRESS, INC. BALTIMORE, MD., U. S. A. THE BIRDS OF ISLA ESCUDO DE VERAGUAS, PANAMA By ALEXANDER WETMORE Research Associate, Smithsonian Institution (With One Plate) Isla Escudo de Veraguas lies in the southern Caribbean Sea at lat. 9°o6' N., long. 8i°34' W., distant a little more than 18 kilometers from Coco Plum Point on the base of the Valiente Peninsula, Prov- ince of Bocas del Toro. The island is roughly rectangular, with a projecting point at the southeast and a somewhat irregular shoreline on the western and northern sides. It is a little over 4 kilometers long by less than i-| wide, with the long axis running east and west. A sand beach extends along three-fourths of the southern side, around the flat, open southeastern point, and across the eastern side, past the mouth of a small stream, to end against a cliff, 12 meters high, of sandy, indurated clay. Similar bluffs separated by short stretches of beach mark the shoreline along the west and north. The northern side is broken by a small bay with a sand beach at its head. On the west the sea has cut back into the land, leaving several small islets, some of them barren except for grass and other low herbage, and some with a crown of brush and trees. Wave action is steadily erod- ing the low cliffs, forming small caves, and in some cases arches that pass through projecting points to the sea on the opposite side. The shallow bank surrounding the island indicates that this process has served to reduce it in size. The land back of the southern beach, elevated sufficiently above high-tide line to form a flat, is fringed with coconut palms on the sea side. Behind these extends low jungle in which scattered trees rise 15 to 20 meters tall. Toward the center the surface is lower and is swampy, with two or three trickles of fresh water, discolored by swamp peat, that drain to the sea. There is a small stand of mangroves at the mouth of the stream that enters the sea above the southeastern point. Columbus during his fourth voyage sighted the island on Oc- tober 17, 1502, when he came out of the Laguna de Chiriqui through Canal del Tigre (Tiger Channel) (Morison, 1942, vol. 2, p. 350). He gave it the name El Escudo as it appeared to resemble an escudo, SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 139, NO. 2 2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 139 or shield. In the following years the island became a landmark for navigators along this stretch of coast, and is mentioned from time to time in ancient documents, the name being abbreviated often to Scudo, Scuda, or sometimes modified to Skoday (Anderson, 191 1, p. 371). Presently it was designated Escudo de Veragua, and finally the latter part of the name became Veraguas. In the last voyage of Sir Francis Drake (Hakluyt, 1904, pp. 239-240) it is related that his ships came to Escudo on January 10, 1596, where they anchored on the southern side, remaining until January 23. The island was described as "not past two leagues long full of wood, and hath great store of fresh water . and that very good." Many of the men soon fell sick, and Drake himself contracted the illness that caused his death on January 28 when they were near Portobello. He was buried at sea off that harbor. In occasional seventeenth-century accounts of buccaneers and other voyagers there is casual reference to Escudo de Veraguas as a place of shelter or a source of water. Dampier's observation (Dampier, 1697, p. 39) made in 1681 that "We past by Scuda, a small Island (where 'tis said Sir Francis Drake's Bowels were bury'd)'' repeats a tale, apparently of common belief, that cannot concern this island since Drake's death and burial, off Portobello, came more than 200 kilometers to the east. Escudo was visited by Indians, since Dr. Matthew W. Stirling of the Smithsonian Institution informs me that in the town of Bocas del Toro he was shown artifacts found on the island, proof that aboriginal people had lived there, at least from time to time. But there may be confusion with some larger place in the report (Anderson, p. 272) that records a considerable Indian population, divided under two caciques or chiefs. The land area, with due allowance for a reasonable amount of erosion since these early times, is too small to have permitted permanent residence for many persons. At present men come at intervals to gather the coconuts, or occa- sionally to fish, search for turtles, or to hunt the introduced wild pigs. There is no permanent human resident, and the wildlife, except for the pigs, is tame. I was able to visit Escudo de Veraguas through the kind assistance of George Munch, manager of the Almirante Division of the Chiriqui Land Co., which has its headquarters at Almirante, Province of Bocas del Toro. We left Almirante on February 28, 1958, shortly before midnight, on the diesel launch Talamanca, entered the sea through the pass of Boca del Toro, and before dawn anchored in the lee on the southeastern end of the island. Accompanied by Ziska Hartmann NO. 2 BIRDS OF ISLA ESCUDO DE VERAGUAS—WETMORE 3 and Jorge Burke, I was ashore near the southeastern point shortly after 7 o'clock and during the forenoon worked through the southern, level section parallel to the beach nearly to the western end. As the sun rose higher the humidity and heat of the dense jungle, where no breeze could enter, became oppressive, so that it was pleasant at the end to walk back to our cayuco along the open beach. At dawn the following morning the breeze blew from the mainland to the south, so that waves were breaking on the beach. We went off before 7 :oo in a choppy sea, and finally landed near the mouth of the small stream. I crossed first into the ridge area at the northeast, but finding this difficult travel and unproductive I sought more level ground. Through this I crossed again toward the western end parallel to the northern shore. The sky was overcast, one shower of rain came, and at times it was difficult to see birds in the heavy jungle shadows. Though there were no trails, the low jungle was open and easy to penetrate. Where the growth became dense the ground was covered heavily with vines. On the north and west the surface rose 10 to 25 meters in broken, steep-sided ridges, separated by little valleys. Here there was much undergrowth of the spiny pita (a plant of the pine- apple family) which, with the steep, slippery slopes, and the swampy floors of the small valleys between, made it difficult to get about. The taller trees that grow along the crests of these ridges from the sea give a misleading appearance of true high forest. On this final day we returned to the launch a little after 11 :oo and, as the sea was rising, left for Almirante, returning through Crawl Cay Channel. The only record of any earlier visit of a naturalist to the island is the skin of a white-crowned pigeon in the collections of the University of California at Los Angeles. From the end of February to early in April 1936, Dr. Loye Holmes Miller of the Department of Zoology of that Institution, on sabbatical leave, accompanied by a graduate student, Frank Richardson, as assistant, visited the Laguna de Chiri- qui, living on a barge that served as a base for a Navy Hydrographic Office detail engaged in a survey of the area. Dr. Miller informs me that on March 2 Richardson accompanied a shore party of Navy per- sonnel to Escudo and brought back a white-crowned pigeon. No other specimens were taken. While Escudo de Veraguas lies well offshore, it is located on a bank where the sea is shallow. A narrow trench of 24 to 35 fathoms lies to the west and southwest, but elsewhere the depths are considerably less. Since it is estimated that sea levels dropped from 90 to 120 meters during the last period of extensive glaciation in Wisconsin 4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I39 time during the Pleistocene, it is apparent that then the island was part of the mainland. A similar connection should have come during part or all of the three preceding periods of maximum glacial ice. Return of warmer temperatures in the interglacial periods, which melted the ice, again raised the water level, placing Escudo once more as an island, remote at sea. It is reasonable to suppose that the resi- dent wren and the manakin, as well as the peculiar spiny rat of the island, were established there during one of the periods of land con- nection, since they are jungle creatures that do not range far from cover, nor are the birds of kinds that would be readily windblown by violent storms. Whether the characters of size and color that now mark them were theirs in whole or in part on their arrival, or whether these are distinctions that have developed during isolation, cannot be said, except that it seems probable that the peculiarity of greater size may have become intensified, since this condition is found regu- larly in populations that seem to have been restricted for long periods to small islands.